Orthopaedics Flashcards
What are stressors of the musculoskeletal system
Trauma
- Sports injuries
- RTA’s
- Overuse
Infection
- Bone and joint
Altered metabolism
- Age related
- Disease related
Neurological
- Muscle spasticity
- Muscle paralysis
what joints can be replaced
All joints
- Upper limb: shoulder / elbow / wrist / hand
- Lower limb: hip / knee / ankle
- Spine: disc replacements
what are the indications for joint replacement
Degenerative disease (e.g. osteoarthritis)
Inflammatory disease (e.g. rheumatoid arthritis)
Trauma (e.g. fracture neck of femur / fracture neck of humerus)
Tumour
Vascular disease (e.g. Avascular necrosis)
Revision of previously failed / worn out joint replacement
what are the three types of joint replacement
cemented
hybrid - cemented stem but acetabulum is uncemented
reverse hybrid - uncemented stem and cemented cup
uncemented
uncemented is more…
expensive but is now more common
how long do joints last
15-20 years
- depends on type of replacement
- type of materials used
what is one of the most common surgical proceeder today
total hip replacement
some joints will always require …
cemented
name a difference between cemented and uncemented
- Cemented = can get the person mobile the next day
- uncemented.=. have to wait for the bone to grow into the porous part of the replacement joint therefore takes 4-6 weeks of non weight bearing on that joint
who is cemented better for
- obese
- elderly
- people with osteoporosis
what polymer is in cemented replacements
Cemented fixation uses an acrylic polymer
Poly(methyl methacrylate) (PMMA)
- can give prophylactic antibiotics to prevent infections
described cemented placement
- both the bone and cement must lock together to make the insertion last
- cement simply acts as a filler between the bone and the implant
describe the uncemented replacement
Uncemented have rough surface covered with porous or hydroxyapatite covering
Maximum bone ingrowth is obtained with pore size 100-200 μm
Gap should be <0.5mm to encourage bone growth
describe the benefit of using ceramic on ceramic as a new biomaterial
- has least wear
- less than 1 um a year -
- fewer infections
- more inert and less likely to start an immune reaction therefore less chance of aseptic loosening
- but small rate of catastrophic failure - over stress ceramic can cause it to collapse
describe other biomaterials that can be used
ceramic on ceramic
Metal on metal
Ceramic in cross-linked polyethylene
Oxinium in cross-linked polyethylene
Metal in cross-linked polyethylene
- 200μm a year
- can lead to aseptic loosening
(listed in the wear and tear rate)
what joint has the least wear rate
ceramic on ceramic
what is the indicators for spinal decompression surgery
Spinal stenosis
Damaged IV disc
Fractured vertebrae
Tumours
what is spinal fusion and what is it for
Where 2 or more vertebrae are joined together with a section of bone to stabilise and strengthen the vertebral column
- won’t affect the movement of the vertebral column as the movement between two vertebra is quite small
What can you use for spinal decompression surgery
bone graft
spinal fusion
IV disc replacement - allow rotational movement
inject bone cement in the centre of the vertebral body that will harden the vertebra
what soft tissue treatments are there
Tendon repair
Tendon transfer
Tendon lengthening
Ligament repair
Ligament replacement
Free muscle transfer
what are the options for tendon transfer for radial nerve palsy
- PT to ECRB for wrist extension
- FCU to EDC for finger MCP extension
- PL to rerouted EPL for thumb extension
Or - PT to ECRL and ECRB
- FDS III to EDC
- FDS IV to extensor indicis and EPL
- FCR to APL and EPB
what is tendon lenghting for
- this is where you have hypertonia in muscle groups
for example - For the lower limb one of the antagonist groups of muscles that are stronger than the other for example the quads are stronger than the hamstring and plantarflexors are stronger than dorsiflexors
Hypertonic plantarflexors – end up toe walking, dorsiflexors cannot counteract it
what can you use for ACL reconstructions
patellar ligament tibia graft,
- goes down from the patellar down the patella ligament to the tibia tuberosity where it inserts, this is meant to heal in quicker as it is bone
- tends to heal quicker
Hamstring
- semitendinous overlies semimembranous therefore you can stitch the muscle to semimebranous underneath it and take the tendon part of semitendinous and use it for the ACL
- gracilis tendon
What is the unhappy triad
Medical mescius
ACL
Medial collateral ligament
